Hat strap sleeve



FIG. 1 is a perspective view of a hat strap sleeve;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The broken lines shown in the drawings illustrate environmental matter and form no part of the claimed design. 

I claim the ornamental design for a hat strap sleeve, as shown and described. 